Scarifier tooth attachment for bulldozers



Oct. 13, 1953 SMALL 2,654,967

SCARIFIER TOOTH ATTACHMENT FOR BULLDOZERS Filed 001?. 7, 1950 2 Sheets-Sheet l {7 2-H 6,1 I 47 17, g1 11 ,FIZ u "E; 1 u

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INVENTOR.

Patented Oct. 13, 1953 SCARIFIER TOOTH ATTACHMENT FOR BULLDOZERS Everett T. Small, Los Angeles, Calif.

Application October 7, 1950, Serial No. 188,980

3 Claims.

This invention relates to scarifying tooth attachments, and to improvements in bulldozer moldboard assemblies including scarifying tooth attachments. The present application is copending with my application for scarifier Tooth Lock, Serial No. 171,785, filed July 3, 1950.

In my previous application there is disclosed a scarifier tooth attachment or assembly which is adapted to be secured to the rear of the moldboard or blade of a bulldozer. In my prior construction there is a housing from which is mounted the scarifier tooth and also a spring pressed plunger which directly engages the tooth for urging the tooth to assume an upright position.

A main object of the present invention is to provide an improved scarifier tooth assembly of the type described in my copending application which is adapted to urge the scarifier teeth to remain in upright positions so that when working on hilly ground the teeth are in proper position to successfully engage the ground for back-ripping purposes.

Another object of the present invention is to eliminate the housing of my prior construction and provide a moldboard having a series of vertical ribs provided with bearings in which a scarifier tooth can be swingably mounted. By such a construction, the weight of the housing is eliminated and the additional weight of the parts of the new device are considerably less than the weight of the housing in my prior construction, and therefore, a saving in weight is achieved.

Another object of the present invention is to provide a scarifier tooth assembly in which a spring pressed plunger is provided, which plunger is arranged to operatively engage a tooth holder which holder receives the tooth. With such a construction the scarifier teeth can be made of a very simple traight-sided design Without having to have the upper ends thereof specially formed to engage a plunger. Also, by providing a holder a superior supporting arrangement for the scarifier tooth is provided for preventing lateral and twisting movements of the scarifier tooth.

Another object of the present invention is to provide an improved lock for locking the spring pressed plunger into its uppermost position.

Another object of the present invention is to provide an improved scarifier tooth assembly wherein there is a holder provided with hollow trunnions fitting in bearings carried by vertical moldboard reenforcement ribs, and wherein the scarifier tooth is detachably secured to the holder by a pin passing through the hollow trunnions and the scarifier tooth.

Another object of the present invention is to provide an improved guide for the lower end of the holder to prevent lateral or twisting movements of the holder.

With the foregoing and other objects in view, which will be made manifest in the following detailed description and specifically pointed out in the appended claims, reference is had to the accompanying drawings for an illustrative embodiment of the invention, wherein:

Figure 1 is a view in elevation taken from the rear of a moldboard embodying the present invention and to which are secured scarifier tooth assemblies embodying the present invention;

Fig. 2 is a sectional view in elevation along lines 2-2 of Fig. 1, showing the manner of attaching the scarifier tooth assembly to the moldboard or bulldozer blade;

Fig. 3 is a sectional view in plan along lines 3-3 of Fig. 2, showing the latching or looking device for the spring pressed plunger of the scarifier tooth assembly;

Fig. 4 is an enlarged view partially in section taken in elevation of a portion of Fig. 1, showing a single scarifier tooth assembly;

Fig. 5 is a view similar to Fig. 2 showing the spring pressed plunger in locked position;

Fig. 6 is a sectional view in plan along lines 6-5 of Fig. 2 showing the guide for the lower end of the holder; and

Fig. '7 is a view in plan similar to Fig. 6, showing a modified form of the guide.

Referring to the accompanying drawings wherein similar reference characters designate similar parts throughout, in Fig. 1 the moldboard or bulldozer blade proper is given the reference numeral l0 and is provided with horizontal reenforcement I I at the top thereof and horizontal reenforcement I2 at the lower end thereof. There are suitable side plates l5 at the sides of the moldboard or blade similar to those shown in my prior application and which side plates are well known in the art.

The moldboard or blade I0 is provided with a plurality of moldboard reenforcement ribs H which are vertically arranged and also arranged in pairs along the back of the moldboard H] to receive the scarifier tooth assemblies.

The scarifier tooth assembly comprises a tooth holder generally entitled 28, best seen in Figs. 1, 2, and 4, which holder has trunnions 2i receivable within bearings 23, which bearings are secured to ribs H. In order to allow easy assembly and disassembly of the scarifier tooth assembly, it is pre ferred that the right-hand bearing shown in Fig.

4 be permanently secured to its rib l1, whereas the left-hand bearing 23 shown in Fig. 4 is secured such as by welding to a bracket 2! which is detachably secured to its rib by means of screws or bolts 29. This construction enables the bearings to be fitted onto the trunnions of the holder 20 at assembly.

There is a channel-shaped guide 39 secured to the lower horizontal reenforcement I2 on the moldboard or blade l and into which the lower end 3| of the holder fits when the holder is in upright position. By upright position it is meant an upright position with respect to the bulldozer blade or moldboard and not necessarily with respect to the ground. When the bulldozer to which the scarifier tooth assembly and moldboard of the present invention are attached is used on hilly ground the bulldozer blade will be raised and frequently when back-ripping is to be performed, the bulldozer blade is at an angle to the ground. At such times, as brought out in my c'o'p'ending application previously identified, it is very desirable that the scarifier tooth be in a position to successfully engage the ground and not merely slide along the ground. The present invention as Well as my prior invention is directed toward a construction which urges the scar'iiier teeth of a moldboard or bulldozer blade to remain in upright position with regard to the bulldozer blade or moldboard during use on hilly ground.

The guide which is of channel shape has rounded corners 33 to make entrance of the holder 3| into the guide 30 easier. The main forces imposed on the scarifier teeth will be imposed during a back-ripping operation and at such time the tooth holder 20 will be disposed within the channel-shaped guide 30, and therefore, the guide 30 will support the holder 20 against lateral or twisting movements and transmit the forces imposed on the scarifie'r teeth to the moldboard Hi.

There are a plurality of teeth 35, one of which is shown in Fig. 4, and the holders 2!] are provided with vertical passages to non-rotatably receive the teeth 35. The teeth 35 have plain shanks of rectangular cross section in the particular embodiment shown, and therefore can be manufactured very cheaply and easily. Tooth 35 shown in Fig; 4 is detachably secured to its holder 25 by a locking pin 31 which passes through trunnions 2| and the upper end of tooth 35'. Pin 31 has a head 38 and a cotter pin 39 securing the pin to the assembly, but of course allowing removal of the pin when it is desired to remove or replace a scanner tooth.

The arrangement in my prior application was such that the spring pressed plunger disclosed therein directly engaged the upper end of a scarifier tooth. With such a construction the upper end of the tooth had to be specially designed to engage the plunger and provide the movements desired. In the present invention there is a roller 40 rotatably supported from holder 20 by a pin 41 which pin is supported by ears 42 of holder 20. There is a spring pressed plunger, generally entitled 45, having a head 46 in engagement with the roller 40 and having a stem 41 extending upwardly therefrom. There is a compression spring 49 surrounding stem 41 and this compression spring is enclosed within a case comprising a lower part 50 and an upper part 5|. The lower part of the case 50 is secured to the head 46 of plunger 45 and is telescopically receivable within the upper portion of the case 5!, said upper part of the case having a web or flange 53 extending therefrom and secured to a bracket 54 which, in turn, is detachably secured by screws or bolts 56 to the left-hand rib I! as the parts are depicted in Fig. 4. There is a nut 59 provided on the upper end of stem 4'! to limit downward movement of plunger 45.

Plunger 45, when in operative position, engages roller and urges the holder 20 and tooth 35 to remain in an upright position so that the tooth 35 may successfully engage hilly soil. However, when working on level ground it is desired to lessen the wear on the parts of the device and therefore means are provided for locking the plunger 45 in an inoperative or raised position. These means comprise a, swingable lock 6| pivoted to web 53 about a pivot pin 64. Lock BI is provided with a semi-circular element 66 which is adapted to fit the stem 41 and fit under the nut 59, and therefore lock the plunger 45 in an inoperative or uppermost position. The plunger 45 may be moved to its inoperative position by merely raising the tooth 35 to the position shown in Fig. 5'.

As can be seen from Fig. 2, the axis of roller 40 is spaced rearwardly of and somewhat downwardly from the axis of trunnions 2| when the tooth holder and tooth are in upirght position. This construction not only results in the tooth being urged by the spring pressed plunger into ah upright position but also allows the tooth and holder to be swung approximately with respect to its upright position without going over center with respect to plunger 45 and thereby avoiding any accidental locking of the tooth and holder in r a horizontal or 90 position. To restate the above,

it is obvious that if the axis of the roller 41 is below the axis of the trunnions that the forces transmitted downwardly by the plunger 45 when the tooth and holder are in the position shown in Fig. 5 will act to cause the tooth and holder to return to their upright position. It is obvious that the axis of the roller must move beyond a vertical linepassing through the axis of the trunni'o'ns in a counterclockwise direction as the parts are viewed in Fig. 5 in order to have over-center action. Therefore, the construction of the present invention allows at least 90 movement from upright position without over-center action.

A bracket or lug 1| is provided on the righthand rib shown in Fig. 4 and aperture 73 is provided through bracket 54 and an aperture 14 is provided in bracket H, said apertures being designed to receive the locking pin 31 to support the tooth 35 in a carrying position, that is a completely inoperative position, so that the bulldozer blade can be used without any operation of the teeth 35.

Teeth 35 have rearwardly directed tips 15 and tip covers or shoes 1! are provided on tips 15.

The description with regard to Fig. 4 and the various parts disclosed in Fig. 4, apply of course to the other assemblies shown in Fig. l which are of the same construction as the assembly shown in Fig. 4.

It is contemplated that the holder 20 may be terminated short of the channel-shaped guide 30 so that, instead of the lower end of the holder fitting within the channel, the 'mid portion of a tooth 35 will fit within a channel-shaped guide designed to receive the tooth.

Although the roller 40 provides an easy operation of the scarifier tooth assembly a sliding arrangement could be provided instead of rolling contact but the roller is the preferred form of the invention and obviously is superior in operation to a sliding engagement although it is possible that the sliding type of arrangement would be somewhat less expensive than the provision of roller.

By the construction shown in the present inventionthe teeth 35 can be readily removed to enable them to be Worked on or replaced by merely removing the locking pins 31. The lateral and torsional forces imposed on the teeth 35 are transmitted to the moldboard or bulldozer blade by the channel-shaped guides 39 which channelshaped guides serve to prevent undue lateral and twisting movements of the teeth 35. The holders 29 also serve to support the teeth 35 and prevent undue lateral or twisting movements of the teeth.

Fig. 7 discloses a modified form of channel guide in which the channel guide [9| has tapered sides 192 to receive the similarly tapered sides N3 of a holder I04.

It will be appreciated that the equivalent of ribs on the back of the moldboard can be provided by suitably recessing the back of the moldboard. The scarifier teeth could then be mounted within these recesses and the sides of the recesses serving the same function as the ribs in the present construction.

Various changes may be made in the details of construction without departing from the spirit and scope of the invention as defined by the appended claims.

I claim:

1. A bulldozer moldboard assembly comprising a bulldozer blade or moldboard, a pair of vertically arranged moldboard reenforcing ribs, a pair of bearings connected to the ribs, a tooth holder having trunnions journalled in the bearings, a scarifier tooth receivable in the holder and detachably secured thereto, a horizontally arranged moldboard reenforcement on the back of the moldboard, a channel-shaped tooth holder guide secured to the horizontally arranged moldboard reenforcement and receiving the tooth holder when the tooth holder is in upright position, a roller on the holder having its axis of rotation spaced backwardly and downwardly from the axis of the trunnions when the holder is in upright position, and a spring pressed plunger secured to at least one rib and engaging the roller to urge the holder into upright position.

2. A scarifier tooth assembly comprising a scarifier tooth, a holder for the tooth, the holder having hollow trunnions, means attachable to the rear of a bulldozer blade rotatably receiving the trunnions to swingably mount the holder, means extending through the trunnions for detachably securing the tooth to the holder, and spring means engaging the holder to urge the holder into upright position.

3. A scarifier tooth assembly comprising a scarifying tooth having a rear'wardly directed tip and a plain shank of rectangular cross section, a tooth holder having a vertical passage therethrough to non-rotatably receive the shank of the tooth, hollow trunnions on the holder extending to the vertical passage, means attachable to the ribs or a bulldozer blade for rotatably supporting the trunnions, a locking pin receivable by the trunnions and passing through the shank of the tooth to lock the tooth to the holder, the pin having a head to limit sliding movement thereof in one direction and a cotter pin to limit sliding movement thereof in the other direction, a roller rotatably supported by the holder and having its axis spaced from but parallel to the axis of the trunnions and disposed rearwardly of and below the axis of the trunnions when the holder is in upright position, a spring pressed plunger engaging the roller to urge the holder to assume an upright position, there being an enlargement on the upper end of the plunger, a swinging lock receivable under the enlargement when the plunger is in its raised position to retain the plunger in its raised position, and a channelshaped guide attachable to the rear of the bull dozer blade and engaging the lower end of the holder when the holder is in upright position to restrain the holder from lateral or twisting movements.

EVERETT '1. SMALL.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,492,140 Morski Apr. 29, 1924 2,297,677 Forte Oct. 6, 1942 2,396,739 McCauley Mar. 19, 1946 2,510,445 Way June 6, 1950 

